Voice mail systems are typically used both as an automated attendant and to record messages for a user or a group of users, e.g. a company, general or receptionist voice mail box. In this regard, the voice mail system can work together with a telephone switch (such as a private branch exchange, PBX, or key service unit, KSU) so that calls will be transferred by the switch to the voice mail system and vice versa. In order to maximize the efficiency of transfers between the voice mail and the switch, blind transfers are preferred. In a blind transfer, if a call is to be transferred from voice mail to another extension, the voice mail port used by the call is released and the call is transferred to the switch immediately. The switch rings the desired extension and transfers the call to that extension if there is an answer. If there is no answer or the extension is busy, then the call is normally routed back to a new voice mail port for further automated attendant handling. The blind transfer allows the released voice mail port to be used by other callers, reducing the total number of voice mail ports that are required in a large system.
In many voice mail systems, as well as a variety of other automated call handling systems, when the automated attendant function is first accessed by an external caller, the caller is provided with a series of options. These options might include a choice of languages for the voice prompts and menu instructions, a selection of touch tone or rotary dial telephone, an account number, a caller type, such as retail customer, wholesale customer, or distributor/agent, and a variety of other options.
A caller is normally presented with a choice by the automated attendant and then the caller dials a selection. For example, the automated attendant might recite “for English dial 1, für Deutsch drück 2, för Svenska välj 3. ” The caller then can select 1, 2 or 3 to send a DTMF tone to the automated attendant. Similarly, the caller can be asked to dial in any other information that will help the automated attendant to serve the caller.
As long as the voice mail system maintains the call, the information provided or selected by the caller can be stored at the voice mail system and associated with the call. When the call is transferred and the voice mail port is reassigned, however, this association is lost. So, for example, if the caller selected a transfer to another extension, was connected to that extension and then transferred back to voice mail, the voice mail system would lose the identification of the call. The caller would be forced to enter language selection, account numbers or any other information again. The same applies to any blind transfer. In the blind transfer, the voice mail system releases the call so that even if the extension to which the call was transferred did not answer and the caller was sent right back to voice mail, the caller would be asked again to enter the language selection and any other selections or information. The loss of the selections and information provided by the caller presents a significant inconvenience to the caller that may result in the caller hanging up in frustration and the caller being lost. At the least, it increases the duration of the call when the caller is reentering information. This consumes more resources of the voice mail system, the switch and the telephone network than would otherwise be necessary.